Working principle of finned tube heat exchanger
Finned tube heat exchanger is a kind of enhanced heat transfer heat exchanger. It relies on the fins outside the tube to enhance the heat transfer on the air side. It is a very economical choice for the occasions where steam and heat transfer oil are used to heat the air. According to the different process conditions, the finned tube heat exchanger can be made of steel pipe wound steel sheet; steel pipe wound aluminum sheet, copper pipe string aluminum sheet, steel-aluminum composite bimetallic fin and other types.
Advantages of finned tube heat exchanger
1. The internal working medium changes phase to realize heat transfer. The fins on the outside of the heat pipe greatly increase the heat transfer area and greatly reduce the convective heat transfer resistance on both sides. It is very economical for the recovery of low-grade heat energy; In addition, the finned tube heat exchanger can easily realize the vertical sweeping flow outside the fluid tube and the pure countercurrent flow of the cold and hot fluids. The average temperature of the cold and hot fluid heat exchange is increased without changing the inlet temperature of the cold and hot fluid. Pressure.
2. The heat transfer surfaces on both sides of the cold and hot fluids can be arranged freely. The heat exchange element of the finned tube heat exchanger is a finned tube. The length of the evaporation section, the length of the condensing section and the fin ratio are independently determined on each side according to the given heat transfer, fluid temperature, flow rate, and the nature and cleanliness of each fluid. , The two sides are not involved in each other. The structure ensures that the finned tube heat exchanger can be used for heat transfer between two fluids with very different temperatures, flow rates and cleanliness.
3. When the heat transfer surface is locally damaged, it can ensure that the two fluids do not mix with each other. During the operation of the finned tube heat exchanger, the cold and hot media are completely separated. During the operation, the single fin tube is worn and corroded. If damage occurs due to over-temperature and other reasons, only a single heat pipe fails, and no hot and cold fluid doping occurs, and it is easy to replace a single finned pipe after it is damaged. Therefore, it is more suitable for flammable, explosive, corrosive and other fluid heat exchange occasions, and has high reliability.
4. It has a high ability to prevent ash accumulation and ash blocking. The flue gas traverses the flow and heat exchange outside the tube, and the disturbance of the flue gas is strengthened. In addition, the temperature of the fin tube wall is high, and the outside of the tube is always in a dry state, so it will not Coking is not suitable for sticking dust, which can effectively prevent clogging.
5. It has high-efficiency resistance to low-temperature corrosion. When the finned tube heat exchanger is used for the waste heat recovery of corrosive flue gas, the temperature of the heat exchange tube wall can be adjusted by adjusting the heat transfer area. Make the heat exchange tube avoid the largest corrosion area as much as possible.
